We have shown that methadone treatment increases ZDV exposure. To enhance the care of opioid dependent patients with HIC infection we are examining interactions between ZDV and other long acting opioids used in the treatment of opioid dependents(1-alpha-acetyl-methadol(LAAM)and buprenorphine). ZDV 200 mg has been administered to non-opioid dependent controls (14) and to subjects chronically maintained on either LAAM (9) or buprenorphine (9). Blood samples have been collected over an 8 hour interval to determine pharmacokinetic parameters of ZDV. Our findings underscore the clinical importance of understanding the interaction of antiretroviral therapies in patients with HIV disease who are chronically maintained on opioids. Data collection is ongoing.